1. Field of the Invention
This invention relates generally to devices displayed in aquariums. More specifically, this invention relates to submerged aquarium action displays.
2. Description of the Prior Art
In recent years, aquarium displays have become increasingly popular. Efforts to enhance the visual appeal of aquariums have resulted in numerous decorative accessories. Among these accessories are various types of sand and gravel fill for lining the aquarium bottom, decorative rock-like formations and countless static and dynamic underwater displays. It has been found that the movement associated with dynamic displays greatly enhances an aquariums visual appearance.
An example of such a device is U.S. Pat. No. 3,057,094, issued to Winkelman, disclosing a submerged waterfall display for aquariums consisting of a structure using air bubbles, produced by a conventional source and injected at the base of an upwardly extending tube, to induce a flow of water and sand into the base of the tube. The upward flow of air bubbles causes the sand, air, and water mixture to rise to the top of the tube where the mixture is then discharged thereby allowing the air bubbles to escape, and the sand to fall back to a catch basin while visible to aquarium observers thus giving the impression of a submerged waterfall. The device, however, requires a bulky domed air cap and an air escape tube that produces a constant stream of air bubbles noticeably escaping the device while returning to the atmosphere.
Similarly, U.S. Pat. No. 3,390,665, issued to Wininger, discloses an aquarium waterfall utilizing, in a like manner, an air source to produce air bubbles which are injected into the lower portion of a vertical tube such that the rising air bubbles induce water and sand to be drawn into the base of the tube and rise to a discharge location. While Wininger eliminates the visible stream of air bubbles escaping beneath the surface of the water, the invention contemplates discharging the bubbles directly at the water surface where they are likely to produce a continuous noise that is not particularly desirable.
U.S. Pat. No. 4,160,427, issued to Holbrook, discloses an aquarium waterfall again using an air source which injects air bubbles at the base of a lift tube such that the rising air bubbles induce water and sand to be drawn into the base of the tube and rise to a discharge location. Holbrook teaches a waterfall simulated by a directed flow of water and sand downward over a simulated cliff having several outcroppings.
While the aforementioned devices have achieved some success in simulating submerged aquarium waterfalls, the prior art devices all possess limitations. For example, all of the devices utilize a compressed air source to inject air into a vertical tube to achieve the lifting effect. As a result, all of the referenced art possess a similar functional limitation in that the air introduced below the water level must be provided with a return path to the ambient atmosphere. In all of the referenced prior art, this method results in the release of air bubbles below the surface of the water. In the Winkelman and Holbrook inventions, this further results in a continuous and visible stream of air bubbles escaping to the surface. While the Wininger invention attempts to conceal the escaping air bubbles from view, the bubbles still produce unwanted noise when breaking the surface of the water.
In addition, the use of rising air bubbles to induce water flow effectively limits the capacity of the system as this method is not capable of producing large water flows. This flow limitation limits the size and quantity of sand particles that can be lifted vertically against gravity. The resulting flow of fine sand is thus relatively small, thereby further limiting the visual effect.
Furthermore, the air utilized by the prior art dictates the use of structures designed to conceal the escaping bubbles. Consequently, the prior art is limited to simulating waterfall like effects with a discharge point either concealed or located sufficiently close to the surface so as to minimize the undesirable visual appearance of rising air bubbles. The foregoing limitation prevents the prior art from effectively simulating an underwater fountain, with a visible discharge point or open fountain head. The instant invention overcomes the this limitation by using pressurized water, in lieu of compressed air, thereby eliminating any undesirable visual appearance resulting from rising air bubbles. As a result, a number of underwater displays, such as fountains and volcanoes, can now be attractively simulated using the instant invention.
Therefore, it is believed that greater visual effect can be achieved by a submerged aquarium display that overcomes the limitations of the prior art by producing larger water flows capable of vertically transporting greater quantities of sand, or larger more visible material such as gravel, without producing distracting air bubbles as a by product.